I have been doing some testing and have loaded a 15 sec AVC Intra 100 clip into FCS3 at all the P2 options for bit rates.

Native shows the correct bit rate of over 100mbs but all the others inc pro res HQ show far lower bit rates.

I then put the native AVC clip on the timeline and it set the system at pro res HQ which is what I would expect but when I do an export to file the bit rate is also very low at 22.4mbs.
This did not happen in FCS2 am I missing something or does FCS3 now compress everything? I havent changed any settings and let FCS3 adjust the timeline to the AVC native clip.

If you are transcoding to ProRes then the bitrate is locked to that particular ProRes codec - it doesn't care what the source was, although I think the bitrate varies with resolution.

If you import in AVCIntra100 native (preference pane in Log & Transfer) then it should still be 100mbps. FCP will report that in MB/s, which should be around 12MB/s.

The odd thing is that you can natively import AVCIntra but there are no AVCIntra sequence presets, so it seems the AVCIntra codec is really just a decoder and you still need to use prores for your sequence.

In you second example you have exported in an MP4 container so who knows what's going on when that happens - it says the codec is "apch." Is that Apache codec? Can you just export a Quicktime of ProRes HQ and check the bitrate of that?

Also I repeated things with just one clip to make it simple and also looked at the file sizes.

So when I look at the data for the native imported 15 sec AVC intra 100 clip it is 212.3mb
When I look at the same clip but transcoded to Pro Res 422 HQ in log and transfer it is only 43.5mb
Putting the AVC intra 100 native clip on the timeline (changes it to pro res HQ) and export to quicktime at pro res HQ the file size is 40.7mb

Thanks in advance for any insights, I may put FCS2 back on one of my machines just to check I am not totally going bit rate mad!

Gary, don't forget that ProRes is a VBR codec ... the actual bit rate and resulting file size for any given clip may vary massively dependent on the actual visual content of the source. Is it possible you're using a less than real world representative source clip for your tests?

Gary, don't forget that ProRes is a VBR codec ... the actual bit rate and resulting file size for any given clip may vary massively dependent on the actual visual content of the source. Is it possible you're using a less than real world representative source clip for your tests?

Thanks Andy that is a good point and may be right as I am using a 15 sec clip of colour bars.

I had a look at some old projects imported as pro res 422 and they are showing a bit rate of around 15MB/S in the FCP window.
I will re-import some of the same media and see if it is any different.